Automatic extensible and collapsible adjustable tap



(No Model.)

P. A. ER'RINGTON. AUTOMATIC EXTENSIBLE AND GOLLAPSIBLE ADJUSTABLE 'IAP.No. 587,715.

Patented Aug. 10,1897.

z o u W a '5 PETERS m, Pworounn. WASHINGYON, n. c,

UNITED STATES PATENT OFFICE.

FRANKLIN A. ERRINGTON, OF EDGElVATER, NEIV YORK.

AUTOMATIC EXTENSIBLE AND COLLAPSIBLE ADJUSTABLE TAP.

SPECIFICATION forming part of Letters Patent No. 587,715, dated August10, 1897.

Application filed May 14, 1895. Serial No. 549,256. (No model.)

To all whom it may concern.- 7

Be it known that I, FRANKLIN ALFRED Ea RINGTON, a citizen of the UnitedStates, residing in the village of Edgewater, (post-office Stapleton,)county of Richmond, State of New York, have invented certain new anduseful Improvements in Automatic Extensible and Collapsible AdjustableTaps, which I desire to secure by Letters Patent of the United States,as described and shown in the following specification and drawings andpointed out in the claims.

My invention relates, broadly, to means for automatically expanding thecutting-jaws of a collapsible tap to the full cutting diameter uponpresenting said jaws to and pressing them against the work and forsimilarly collapsing said cutting-jaws by utilizing the spiral action ofthe angular pitch of the cutting-teeth of said jaws, in combination withthe formation of the supporting part or arbor and the resistance of thework, to move said jaws longitudinally and inwardly for said purpose,together with means for adj usting the same device for holes of variousdiameters and depths. In contradistinction to all previously-knowncollapsible taps, which can be utilized for only one size hole, andwhich have to be expanded either by hand 01' by reversing the directionof rotation of the driving part, in the device here illustrated anddescribed the jaws are rigidly supported while cutting, automaticallyrebound to enable them to be automatically expanded to the diameter forwhich they are adjusted, automatically protect themselves from jammingwhen the tap bottoms, &c., and the device is consequently atall timesready to answer the will of the operator.

To these ends the invention consists in the novel details of improvementand the combination of parts, that will be more fully hereinafter setforth, and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming parthereof, wherein- Figure 1 is a vertical cross-section on the line 3 3 ofFig. 2 of a device constructed in accordance with my invention,showingthe cutting-jaws T Tin the working position ready for bottom tapping.Fig. 2 is an end view of Fig. 1, showing the extension S flattened toreceive the clamp J upon the inclined plane a. Fig. 3 is a top view ofFig. 1, showing the angular pitch m z of the cutting-teeth t of jaw T,the fiuting of the arbor S to facilitate the removal of the chips, thecone-like outline of extension S, &c. Fig. 4 is a vertical cross-sectionof a tube or pipe R with its driving or holding means B B. Fig. 5 isacross-sectional view of the application of my invention to taps ofsmaller size, showing also the method of connection with driving orholding means M. Fig. 6 is an end view of Fig. 5. Fig. 7 is a sectionalview of Fig. 5, showing the parts in the collapsed position aftercompleting the threading of the bottom hole H in rod It, showing thedevice without a spring, toillustrate not only what I consider the bestconstruction in small sizes, but the desirability of the automaticrebound where practicable; and Fig. 8 is a sectional View of the end ofFig. 1, showing arbor S with an adjustable end G to enable the device totap holes of varying depths without danger of breakage, (be.

In the application of my invention herein shown the letter S indicatesan arbor, which has a longitudinal slot or slots 8, formed with thebottom of said slots at an angle to the axis of said arbor to afford aninclined plane or planes a, having a common apex A. To obtain a widerange of adjustment, the inclined plane CL of arbor S may be prolongedon an extension S. The sides of the slot or slots 5 in arbor S aredesigned to receive the lateral cutting strain of a jaw or jaws T. Theextension S may be a simple cone rising from the periphery of the arborS and having an apex at A common with the bottom of the slots 5, thesurface of said cone thus ext-ending the inclined plane a, or the arborS may itself be coned as a continuation of cone S, and the lateralstrain of the cutting-jaws T taken up by the clamps J, being firmlysecured to said cone for that purpose, or the construction of the partsmay beotherwise varied without deviating from the spirit of myinvention. The extension S is here preferably shown flattened to providea surface to receive the clamp J in the inclined plane a, where saidclamp is securely held in place by suitable clamping means, such as thebolt I. To permit the use of the ordinarybolt for this purpose, thetapered blocks 2" are provided with a hole fitting bolt I and are theninterposed to distribute the pressure of bolt I and increase thefrictional contact between clamp J and arbor S. Where the extended rangeof such a device as Fig. 1 is not required, the extension S may beomitted or the simple construction of Figs. 5 and 7 util workingposition with the axis of the arbor S, although the serratedcutting-face of a plug-tap may itself be tapered somewhat where it firstencounters the work or be otherwise irregularly formed, as is customaryin such and similar tools. The inclined top 6 of cutting-jaw T is shownparallel with the back I) of said jaw and is provided with a projectionor lug V. The cutting diameter of the teeth t is regulated by theposition of the surface 10' of the clamp J, which receives the thrustof' the lug V. The lug V is for the purpose of controlling thelongitudinal movement of the jaw T. The cutting-teeth t of the jaw T areformed at any desired angle or spiral pitch at z to the axis of arbor S,and upon the rotation of either arbor S or the work R, (either having anequivalent effect,) after one or more threads 77/ have been cut in thework and the longitudinal movement of arbor S is stopped, (by the end Gof said arbor encountering the bottom of the hole h or otherwise,) saidangular pitch of said cuttingteeth will operate to move said jaw Tindependently along said inclined plane a, and the resistance of themetal to the cut of said teeth will tend to press the beveled back b ofsaid jaw against the inclined plane a, and the cutting-jaw T willthereby be moved automatically along and down the inclined plane tountil the teeth if are freed from the back pressure exerted by theirangular pitch while rotating against the threads that have been cut andthe tap will be in its collapsed position (see Fig. 7 ready to bewithdrawn from the work.

By the lug V encountering the surface 10 of clamp J when the tap iswithdrawn the cutting-jaw T is prevented from escaping from its properposition upon arbor S, the distance between the surfaces to and w ofslot \V being at least equal to the distance traveled longitudinally byjawT in moving from its working to its collapsed position, (see Figs. 5and 7,) and it is advisable to have said space or slot somewhat exceedsaid distance as a margin of safety, as the longitudinal back pressureof the angular pitch of the teeth against the threads that they havealready cut, while here utilized to move said jaws independentlytocollapse the tap, would serve to strip said threads or break said jawsit said teeth if were not clear of the threads h before lug Vencounteredthe surface to or the end G met the bottom of the hole h after thelongitudinal movement of arbor S is stopped by end G, face D, orotherwise.

As shown in Fig. 7, after the jaw T. has been collapsed it will remaincollapsed until the serrated teeth tare again projected beyond the arborS, and that if only slightly,

raised beyond said periphery they will then expand to their normalworking position upon being pressed against the work. In thesmallersizes the sensitiveness of the threads and the ease with whichthe single jaw can be manipulated, especially-when the work revolves andthe tool is non-rotary, as on a turret-lathe, make the simpleconstruction of Fig. 7 the most desirable. When the tap is to be used ona drill-press, where the tool revolves and the work is stationary, it isdesirable to have the jaws rebound automatically to a sufficient degreeto extend them beyond the periphery of arbor S to enable them toencounter the edge of the hole H, and thus be pressed backward andexpanded outward to their normal cutting size. This automatic reboundshould be so slight as to avoid stripping or unduly wearing the threadsh after the jaws are collapsed, and yet suflicient to move the jaws to aposition where they can be automatically readjusted to the cut bypressure against the work, and for this purpose I have inserted spiralsprings W in space or slot W between projection or lug V and the surfacew, (see Figs. 1 and 5,) although the spring might be otherwise arrangedfor the same purpose. This springis preferably shown shorter than thedistance between the surfaces 10 and the lug V when the jaw T is in fullworking position, so that the action of the spring is very slight whenthe tap is collapsed, yetis most powerfully exerted when the tap isbeing withdrawn from the work, so that when the jaw'T clears the threadsh the spring will cause the jaw to rebound sufficiently to be readilyand automatically reexpanded, as previously. explained. Thus it will beseen that while this automatic rebound is-desirable in many cases yet itis not an essential to the coaction of the other improvements of myinvention, which are operative without this feature under many usefulconditions.

As shown, the clamp or clamps J have a slot j, permitting them to bemoved up and down the inclined plane a to adjust the cut-.

be readily controlled by hand the slot \V is extended up through thesurface of clamp J and the lug V projected beyond said clamp, so that itcan be readily grasped by the operator. YVhen used as a pipe-tap, theface D of the clamp J may be used to regulate the depth the arbor S goesinto the hole H of a pipe R and by arresting the longitudinal movementof arbor S permit the jaw T to collapse automatically, as abovedescribed; and when used on a bottom hole, as 7L, in red R, Fig. 7, theend G of arbor S operates to produce the same eiteet. Both the end G orthe face D may be made adjustable by such means as shown in Fig. 8,where the screw or stop-piece G is moved out of or into the hole g tocollapse the jaws T sooner or later, as desired.

To explain the coaction of the several parts, as herein shown, the arborS, Fig. 5, is adapted for connection with suitable holding or drivingmeans M, and the tube or red B may be similarly held or driven by themeans B. Where the means M for holding arbor S are connected with thelongitudinally-movable rotative spindle of a drill press, and the means13 with the stationary jaws of a chuck to hold the tube R rigidly, thearbor S will be moved forward and rotated to the right (to the left forleft-hand threads) and the cutting-jaw T presented to one side of thebore H. Then the surface F of arbor S (or the opposite jaws in the caseof two or more jaws, as in Fig. 1) will be pressed against the otherside of said hole, and the continued longitudinal pressure on the arborS and the rotation of the tap will cut the threads h". When the end G orG of spindle S (or face D of clamp J in the case of a pipe or throughhole H, Fig. 4E) encounters the bottom 71 of bore H, (see Fig. 7,) thecontinued rotation of the tap will enable the angular pitch of its teethto coact with the threads already cut to move the jaw T longitudinally,as above described, and collapse the cutting-teeth of said jaw untilthey clear the work, where they may revolve harmlessly untilthe arbor Sis moved backward from the work, when the lug V engages the surface 20(or spring W) and the whole device is withdrawn without reversing themotion of the rotating part, which in this case would be the arbor S,which at all stages of the operation continues to rotate in the samedirection as originally started. As the jaws T continue to revolve it isdifficult, if not impossible, to expand them by hand without stoppingthe machine, and it is therefore desirable to have them reboundsufficiently after leaving the hole H to enable them to encounter theedge of the next hole H upon being again presented to the work, and thismay be accomplished by spring XV or similar means for this purpose, asexplained above.

lVhere the means M for holding arborS is the longitudinally-movablenon-rotary turret of a turret-lathe and the means B for holding the workR the rotative jaws of a chuck that connect the work R with the rotativelive-head of said lathe or similar machine, the arbor S would notrotate, but be simply pressed against and into the hole H, and as therod R revolved against the teeth 25 the threads It would be cut, asheretofore, the only difference being that the arbor S is not rotated inthis case and the work is, whereas in the previous case the arbor Srotated and the work did not. In this last position on a turret-lathe itwill be seen that as the jaw or jaws T do not rotate the operator canreadily expand them by his hand on the lug V suffieiently to enable themto encounter the edge of the hole H when again presented to the work R,should it not be desirable for any reason to employ the spring V forthat purpose. (See Fig. 7.)

The ability to regrind the parts and reset them in their respectiveplaces to a nicety makes the simplicity of my device particularlydesirable, while the movable clamp and the rigidity obtained by havingthe jaws at all times during their cutting action sup-v ported by afixed arbor S, with its inclined plane a, secure an accuracy andevenness of cut and a readiness of adjustment not heretofore met with indevices havingan independently-movable supporting-piece instead of myindependently-movable cutting-jaw.

While my invention is here shown as applied to a serrated jaw, it isobvious that it is equally applicable to any description of cutting-jaw.

Having now described my invention, what I claim is 1. The combination ofan arbor, a cuttingjaw connected to rotate therewith, retaining means topreserve the connection of said jaw with said arbor, said arbor havingvariations in its diameter under said jaw to coact with similarvariations in the depth of said jaw, and said jaw being longitudinallymovable independently both of said arbor and of said retaining means forsuch a distance as will enable said jaw to expand to or collapse fromthe cutting position, substantially as described.

2. The combination of an arbor, a cuttingjaw connected to rotatetherewith, a clamp connected with said arbor to retain said jaw thereon,said arbor having variations in its diameter under said jaw to coactwith similar variations in the depth of said jaw, and said jaw beinglongitudinally movable independently both of said arbor and of saidclamp for such a distance as will enable said jaw to expand to orcollapse from the cutting position, substantially as described.

3. The combination of an arbor, a cuttingjaw connected to rotatetherewith, said arbor having variations in its diameter under said jawto coact with similar variations in the depth of said jaw, anda clampconnected with said arbor to retain said jaw thereon, said jaw and oneof said other parts having respectively the one a slot and the other aprojection meshing with said slot, the longitudinal dimension of saidslot being sufliciently greater than the corresponding dimension of saidprojection to permit said jaw to move longitudinally independently ofboth said arbor and said clamp for such a distance as will enable saidjaw to expand to or collapse from the cutting position, substantially asdescribed.

A. The combination of an arbor, a cuttingjaw connected to rotate withsaid arbor, corresponding variations in the diameter of said arbor undersaid jaw and in the depth of said jaw, a clamp adjustable longitudinallyon said arbor, and means to fasten said clamp rigidly to said arbor atcertain intervals in the length of the latter to vary the position ofsaid jaw thereupon, said jaw being movable longitudinally independentlyboth of said arbor and of said clamp for such a distance as will enablesaid jaw to expand to or collapse from the cutting position,substantially as described.

5. The combination of an arbor, a longitudinally-movable cutting-jawconnected to rotate therewith, said jaw having teeth extending at anangle to the axis of said arbor, said arbor having variations in itsdiameter under said jaw to coact with similar variations in the depth ofsaid jaw, retaining means to hold said jaw in connection with saidarbor, and a stop-piece to coact with said parts to cause said jaw tomove longitudinally along 1 said arbor during operation to collapseautomatically, substantially as described.

6. The combination of an arbor, a longitudinally-movable cutting-jawconnected to rotate therewith, said jaw having teeth extending at anangle to the axis of said arbor, said arbor having variations in itsdiameter under said jaw to coact with similar variations in the depth ofsaid jaw, a clamp to retain said jaw in connection with said arbor, anda stop-piece connected with said arbor and projecting beyond said jaw tocause said jaw to move longitudinally along said arbor during operationto collapse automatically, substantially as described.

7. The combination of an arbor, a cuttingjaw connected to rotatetherewith, one of said parts being movable longitudinally independentlyof the other, said arbor having variations in its diameter under saidjaw to coact with similar variations in the depth of said jaw, retainingmeans to hold said jaw inconnection with said arbor, and a spring tocoact with said parts to cause said jaw to rebound automatically fromthe collapsed position, substantially as described.

8. The combination of an arbor, a cuttingj aw connected to rotatetherewith, one of said parts being movable longitudinally independentlyof the other, said arbor having variations in its diameter under saidjaw to coact with similar variations in the depth of said jaw, a clampto retain said jaw in connection with said arbor, and a spring locatedbetween said parts to cause said jaw to rebound automatically from thecollapsed position, substantially as described.

9. The combination of an arbor, a cuttingjaw connected to rotatetherewith, one of said parts being movable longitudinally independentlyof the other, said arbor having variations in its diameter under saidjaw to coact with similar'variations in the depth of said jaw, a clampto hold said jaw in connection with said arbor, one of said parts havinga slot and another of said parts having a projection or lug meshingtherewith, the longitudinal dimension of said slot being greater thanthe corresponding dimension of said lug, and a spring located betweensaid parts to cause said jaw to rebound automatically from the collapsedposition, substantially as described.

10. The combination of an arbor, a longitudinally-movable cutting-jawconnected to rotate therewith, said arbor having variations in itsdiameter under said jaw to coact with similar variations in the depth ofsaid jaw, a

clamp having a slot W, passing through it, said jaw having a lug V,passing throughsaid slot W, in said clamp and extending beyond thesurface of said clamp, said slot W, being'of greater length than thecorresponding dimension of said lug V, substantially as described.

F. A. ERRINGTON. WVitnesses:

THEODOR D. WILSON, BENJ. W. EATON.

